US7405015B2ExpiredUtilityPatentIndex 65

Ionomer for use in fuel cells and method of making same

Assignee: GORE ENTERPRISE HOLDINGS INCPriority: Jul 5, 2001Filed: Jul 5, 2002Granted: Jul 29, 2008

Est. expiryJul 5, 2021(expired)· nominal 20-yr term from priority

Inventors:XIAO GUYU SUN GUOMIN YAN DEYUE ZHU XINYUAN MARTIN CHARLES W WU HUEY GULATI KARINE CAVALCA CARLOS ALBERTO

C08J 5/22H01M 8/10H01M 4/88Y02P70/50H01M 8/103H01M 8/1032H01M 4/92H01M 8/1004C08J 2379/00C08J 5/2256Y02E60/50C08J 5/2275H01M 8/1027H01M 4/8605

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Claims

Abstract

The reaction product of a monomer comprising phthalazinone and a phenol group, and at least one sulfonated aromatic compound. The monomer comprising phthalazinone and a phenol group is used in a reaction with the sulfonated aromatic compound to produce ionomers with surprising and highly desirable properties. In one embodiment, the inventive ionomer is a sulfonated poly(phthalazinone ether ketone), hereinafter referred to as sPPEK. In another embodiment, the inventive ionomer is a sulfonated poly(phthalazinone either sulfone), herein after referred to as SPPES. In another embodiment, the inventive ionomer is other sulfonated aromatic polymeric compounds. The invention further includes the formation of these polymers into membranes and their use for polymer electrolyte membrane fuel cells (PEMFC), and in particular for direct methanol fuel cells (DMFC). The inventive polymers may be manufactured in membrane form, and can be dissolved into solution and impregnated into porous substrates to form composite polymer electrolyte membranes with improved properties.

Claims

exact text as granted — not AI-modified

1. An ionomer comprising the reaction product of monomer A with monomer B and C, wherein the moles of monomers B plus C equal the moles of A, wherein R 1-4 are independently H, linear or branched alkyl, aromatic, or halogen; X 1 and X 2 are independently a carbonyl or sulfone radical or aromatic compounds connected through a ketone or sulfone linkage; Y is independently a halogen group, and M is an alkali metal

2. An ionomer as defined in claim 1 wherein monomer A comprises 4-(4-hydroxyphenyl) phthalazinone.

3. An ionomer as defined in claim 1 wherein monomer B comprises disodium 3,3′-sulfonyl(4,4′-difluorobenzophenone).

4. An ionomer as defined in claim 1 wherein monomer C comprises 4,4′-difluorobenzophenone.

5. An ionomer as defined in claim 1 wherein monomer A comprises 4-(4-hydroxyphenyl) phthalazinone, monomer B comprises disodium 3,3′-sulfonyl(4,4′-difluorobenzophenone), and monomer C comprises 4,4′-difluorobenzophenone.

6. An ionomer as defined in claim 1 wherein monomer B comprises disodium 3,3′-sulfonylbis(4-fluorophenyl sulfone).

7. An ionomer as defined in claim 1 wherein monomer C comprises bis(4-fluorophenyl)sulfone.

8. An ionomer as defined in claim 1 wherein monomer A comprises 4-(4-hydroxyphenyl) phthalazinone, monomer B comprises disodium 3,3′-sulfonylbis(4-fluorophenyl sulfone), and monomer C comprises bis(4-fluorophenyl)sulfone.

9. An ionomer comprising the reaction product of monomer A with monomer B and C in an azeotroping solvent mixed with an inert aprotic polar solvent containing at least 2 moles of an alkali metal base for each mole of monomer A, wherein the moles of monomers B plus C equal the moles of A, said reaction driven to completion by the azeotropic removal of water at a temperature above the azeotropic boiling point of the azeotroping solvent in the presence of water, wherein R 1-4 are independently H, linear or branched alkyl, aromatic, or halogen; X 1 and X 2 are independently a carbonyl or sulfone radical or aromatic compounds connected through a ketone or sulfone linkage; and Y is a halogen group

10. An ionomer comprising the reaction product of monomer A with an ionomer-contributing monomer

wherein R 1-4 are independently H, linear or branched alkyl, aromatic, or halogen.

11. An ionomer as defined in claim 10 wherein said ionomer-contributing monomer comprises sulfonic acid.

12. An ionomer as defined in claim 10 wherein said ionomer-contributing monomer comprises carboxylic acid.

13. A sulfonated Poly(phthalazinone ether ketone) s, comprising repeating units of the polymers shown below:

wherein R 1 and R 2 are selected from hydrogen atom, alkyl group, or aromatic group and M is metallic base ion.

14. A method of preparing a sulfonated poly(phthalzinone ether ketone) comprising the steps of
(a) copolymerizing 4,4′-dihalo (or dinitro)-3,3′-disulfonate salt of benzophenone, dihalo (or dinitro) benzophenone, and a monomer containing phthalazinone and phenol group, in polar solvents or reaction medium containing mainly polar solvents, in the presence of a catalyst comprising a metallic base (or its salt), to obtain a product;
(b) dehydrating said product at high temperature using azeotropic dehydration agents;
(c) diluting said product with solvents;
(d) coagulating said product using coagulation agents;
(e) separating said product;
(f) drying said product; and
(g) performing steps (c) through (f) two additional times to obtain said sulfonated poly(phthalazinone ether ketone).

15. The preparation method of claim 14 , wherein the reaction temperature is 150-220° C. and the reaction time is 4-32 hours.

16. The preparation method of claim 14 , wherein the polar solvents are dimethyl sulfoxide, tetramethylene sulfone, phenyl sulfone, 1-methyl-2-pyrrolidinone, N,N-dimethylformamide.

17. The preparation method of claim 14 , wherein the azeotropic dehydration agents are selected from the group consisting of toluene, xylene, and chloroform.

18. The preparation method of claim 14 , wherein the coagulation agents are water and one of the group of methanol and ethanol.

19. A sulfonated poly(phthalazinone ether sulfone) comprising repeating units of the polymers shown below:

wherein R 1 and R 2 are selected from hydrogen atom, C1-C4 linear or branch alkyl group, or aromatic group, M is sodium or potassium ion, m+n.&gt; or =20.

20. A method of preparing a sulfonated poly(phthalazinone ether sulfone), comprising the steps of
(a) copolymerizing 4,4′-dihalo (or dinitro)-3,3-disulfonate salt of phenyl sulfone, dihalo (or dinitro) phenyl sulfone, and a monomer containing phthalazinone and phenol group, in polar solvents or reaction medium containing mainly polar solvents, in the presence of a catalyst comprising a metallic base (or its salt), to obtain a product;
(b) dehydrating said product at high temperature using azeotropic dehydration agents;
(c) diluting said product with solvents;
(d) coagulating said product using coagulation agents;
(e) separating said product from said agents;
(f) drying said product; and
(g) performing steps (c) through (f) two additional times to obtain said sulfonated poly(phthalazinone ether sulfone).

21. The preparation method of claim 20 , wherein the monomer containing phthalazinone and phenol group has the following molecular structure:

wherein R 1 and R 2 are selected from hydrogen atom, C1-C4 linear or branch alkyl group, or aromatic group.

22. The preparation method of claim 20 , wherein the reaction temperature is 140-220° C. and the reaction time is 1-36 hours.

23. The preparation method of claim 20 , wherein the polar solvents are dimethyl sulfoxide, tetramethylene sulfone, phenyl sulfone, 1-methyl-2-pyrrolidinone, and N,N-dimethylformamide.

24. The preparation method of claim 20 , wherein the azeotropic dehydration agents are toluene, xylene, or chloroform.

25. The preparation method of claim 20 , wherein the coagulation agents are water and methanol (or ethanol).

26. A method for generating electricity comprising the steps of:
(a) providing an anode;
(b) providing a cathode;
(c) providing a polymer electrolyte membrane between said anode and said cathode and in communication with said anode and said cathode, said polymer electrolyte membrane comprising the ionomer of claim 1 in acid form
(d) flowing a fuel to said cathode where said fuel is disassociated to release a proton and an electron;
(e) transporting said proton across said polymer electrolyte membrane to said anode; and
(f) collecting said electron at a collector to generate electricity.

27. A method as defined in claim 26 wherein said polymer electrolyte membrane comprises a polymeric support having interconnected passages and pathways that are substantially occluded by said polymer.

28. A method as defined in claim 26 wherein said polymeric support is expanded polytetrafluoroethylene.

29. A method as defined in claim 26 wherein said fuel is methanol.

30. A method as defined in claim 26 wherein said fuel is hydrogen.

31. A method as defined in claim 27 wherein said fuel is methanol.

32. A method as defined in claim 27 wherein said fuel is hydrogen.

33. A method as defined in claim 28 wherein said fuel is methanol.

34. A method as defined in claim 28 wherein said fuel is hydrogen.

35. A polymer electrolyte membrane comprising the ionomer of claim 1 in acid form.

36. A polymer electrolyte membrane as defined in claim 35 further comprising a polymeric support having interconnected passages and pathways that are substantially occluded by said ionomer.

37. A polymer electrolyte membrane as defined in claim 36 wherein said polymeric support is expanded polytetrafluoroethylene.

38. A membrane electrode assembly comprising:
(a) an anode;
(b) a cathode; and
(c) a polymer electrolyte membrane between said anode and said cathode and in communication with said anode and said cathode, said polymer electrolyte membrane comprising the ionomer of claim 1 in acid form.

39. A membrane electrode assembly as defined in claim 38 wherein said polymer electrolyte membrane comprises a polymeric support having interconnected passages and pathways that are substantially occluded by said ionomer.

40. A membrane electrode assembly comprising:
(a) an anode;
(b) a cathode; and
(c) a polymer electrolyte membrane between said anode and said cathode and in communication with said anode and said cathode; wherein at least one of said anode and said cathode comprises the ionomer of claim 1 .

41. A membrane electrode assembly comprising:
(a) an anode;
(b) a cathode; and
(c) a polymer electrolyte membrane between said anode and said cathode and in communication with said anode and said cathode, said polymer electrolyte membrane comprising the ionomer of claim 1 in acid form,
(d) wherein said polymer electrolyte membrane has a relative selectivity factor greater than 1.0.

42. A membrane electrode assembly as defined in claim 41 wherein said relative selectivity factor is about 1.3.

43. A membrane electrode assembly comprising:
(a) an anode;
(b) a cathode; and
(c) a polymer electrolyte membrane between said anode and said cathode and in communication with said anode and said cathode, said polymer electrolyte membrane comprising the ionomer of claim 5 in acid form.

44. A fuel cell comprising the membrane electrode assembly of claim 38 sandwiched between a first gas diffusion medium and a second gas diffusion medium, said membrane electrode assembly being in electronic communication with a current collector.

45. A fuel cell as defined in claim 44 wherein said polymer electrolyte membrane comprises a polymeric support having interconnected passages and pathways that are substantially occluded by said ionomer.

46. A fuel cell as defined in claim 45 wherein said polymeric support is expanded polytetrafluoroethylene.

47. A fuel cell as defined in claim 44 wherein said fuel cell is a direct methanol fuel cell.

48. A fuel cell as defined in claim 44 herein said fuel cell uses hydrogen as a fuel.

49. A fuel cell as defined in claim 45 wherein said fuel cell is a direct methanol fuel cell.

50. A fuel cell as defined in claim 45 wherein said fuel cell uses hydrogen as a fuel.

51. A fuel cell as defined in claim 46 wherein said fuel cell is a direct methanol fuel cell.

52. A fuel cell as defined in claim 46 wherein said fuel cell uses hydrogen as a fuel.

53. A fuel cell as defined in claim 44 having an open circuit potential of 0.704 V.

54. A fuel cell as defined in claim 44 having an average methanol crossover measurement of about 0.124.

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